Reduction of elongated bodies



Oct. 26, 1943. P. H. HUME REDUCTION OF ELONGATED BODIES Filed Jan. 25,1941 s Sheets-Sheet 1 1720021507: PAYTE/CK HUME,

O 2 1943. P. H. HUME 2, 332Q796 REDUCTION OF ELONGATED BODIES Filed Jan.25, 1941 3 Sheets-Sheet 2 [ill/676(0)? Hare/6K fi umg,

1 Oct 1943. P. H. HUME 2,332,796

REDUCTION OF ELONGATED BODIES Filed Jan. 25, 1941 3 Sheets-Sheet 3 [mmafar: Pare/CK H /M,

Patented Oct. 26 1943 1 REDUCTION OF ELONGATED BODIES Patrick H. Hume,Lakewood, Ohio, assignor to Carnegie-Illinois Steel Corporation, acorporation of New Jersey Application January 25, 194i, Serial No.376,001 27 Claims. (01. 80-32) the like, which, for purposes of thisdescription,

may be regarded synonomously.

Heretofore sheet, strip, wire, etc., have, in the metal industries, beenproduced by movement through a compressive means such as rolls or dies,to reduce the metal section an amount provided by such dies. In someinstances, the stock being reduced has been subjected to a tensionthroughout its extent, while being acted upon by such dies, partially toalleviate the compressive stresses at this point, and to bring about amore efficient operating condition. In the case of wire, or very narrowstrips, tension in excess of the yield point of the material has beenused with some success without the aid of dies. In all other cases, thetension has been applied incidental to the application of thecompressive forces, which, for any given reduction, usually remainssubstantially constant. The stretching of wire without the benefit ofcompressive dies has not proved, to be desirable in all instancesbecause of the lack of control over the necking-down" of the material,which is inclined to take place at mechanically weak portions of thewire to cause breakage of the stock before contiguous portions have beenreduced the required amount.

With respect to the application of tensile forces where compressive diesare used, the amount of such forces has, in the past, been more or lessarbitrary, with no definite correlation of the compressive forces to thetensile forces, or vice verse, to give effect to the most eflicientcondition for reduction. Thus, in the reduction of strip, tension isapplied without direct regard to the compressive force being exerted bythe work rolls upon the material, and usually remains constantthroughout the operation, irrespective of the screw-down pressure bywhich the work rolls areforced to bear upon the strip. More or lessreduction is, therefore, made by adjustment of the roll screw-downswithout I effecting any change in the tension of the strip.

' set of conditions.

In wire drawing operations, the apparatus employed is usually such as togive a predetermined tension for any wire drawing operation, even thougheach operation necessarily varies as the size of the wire being drawn,and the size of the dies through which it is being drawn, vary.

, It is, thus, possible to tear a strip in half during the rollingoperation by applying to it the same tension formerly usedsatisfactorily in the reduction of a heavier section, or with lessscrewdown pressure, since the tensile force, when combined with theaugmented compressive force, causes the strip to rend in two. Similarly,in wire drawing, the tension applicable for one set of conditions maybeinacceptable for an altered In either case, it is possible that thematerial would be subjected either to a tension overload, causing itsfailure, or would be given too little tension, which is improvident ofthe most eificient reducing action.

Similarly, in reducing operations wherein com pressive dies areemployed, which are adjustable to vary the amount of reduction effected,as in rolling mills, it has heretofore been virtually impossible topreset the mill in accordance with all known factors to give the precisereduction in thickness, and extension in length, required in any givenoperation. To circumvent this difficulty, many elaborate and costlymechanisms have been devised to gauge the amount of the reduction bymeasuring the thickness of the material before and after reduction or tomeasure the extension of the material resulting from the reduction, orto compare the rate of movement of the reduced material with the rate ofmovement of the unreduced material, from which the reduction can becomputed. Such instrumentalities are, at best, suitable only for theempirical determination of a reducing operation then in progress, but'are of no assistance in presetting a mill to give a stock having theprecise cross-sectional area and length desired.

It is the primary object of the present invention to provide a methodandmeans for reducing a cross-sectional area of, and for elongating,

materials of the class described in a manner that removes all of theuncertainties and ob- Jections experienced heretofore in similaroperations.

It is another object of the present invention to provide a method andmeans for effecting such reductions in a manner that effects correlationbetween the tensile and compressive forces existent during the reducingoperation so operating conditions.

It is another object to improve upon presentday rolling mill techniqueby simplifying the operations, and by affording absolutely uniformexisting modes of reducing long sections of flexi- (r ble material, suchas steel strip, so that the operation is carried out with the maximumefliciency and convenience, whereby a better prod-, uct as to physicalproperties and surface finish is realized. Still other objects andadvantages are implicit in the following presentation.

In the accompanying drawings several diagrammatic representations ofapparatus for giving effect to the presentinvention are shown. Thus.Figure 1 is a schematic illustration, as viewed at side elevation, of arolling mill designed to illustrate the principles of the invention.

Figures 2 to 5, inclusive, are views corresponding to Figure 1, whichillustrate modified forms of the invention.

Figures 6 to 9 show the principles hereof as applied in slightlydifferent forms from that contemplated in the foregoing figures, butcorresponding in viewpoint to the latter.

Referring now more particularly to the drawings in which like referencecharacters are used to identify like parts throughout:

In the embodiment of the invention shown in Figures 1, 2 and 3, there isprovided idle work rolls l, 2 and 3, to which a supply of material .8,capable of plastic deformation, such as steel strip. is delivered from acoil 4 in such a manher that it iscaused to pass beneath the roll I;thence, upwardly between the rollsl and 2; around the periphery of thelatter; downwardly between rolls 2 and 3, and, thence, around the latterto a take-up 5. e

The rolls I and 3 are mounted upon stationary axes of revolution, whichmay be adjustable backwards and forwards in the direction of the arrows6 to vary the spacing therebetween. The work r0112 is supported by therolls l and 3, and, thus, is free to move in vertical directionsindicated by the arrow 1. From this arrangement, it will be appreciatedthat, as the strip is moved in either direction between stations 4 d 5,any'tension therein will be transmitted throughout the length thereof tocause the work roll 2 to move downwardly to compress the strip betweenitself and the relatively stationary rolls l and 3. If the tension inthe strip S, is increased, the compressive forces to which the strip issubjected between the several rolls is increased in directproportionthereto and as the tension is lessened. thecompressive force with whichthe roll -'I bears upon the rolls l and 3 is likewise lessened, and,except for the weight of the-parts, amounts to zero at zero tension.

This provides a simple, and yet effective, cor- 2,332,796 asautomatically to establish the most efllcient adjusting the tension, togive the precise reduction required. Although there is no limitation asto which direction the mill in Figure 1 might run, and might well bedesigned as a reversing mill, it has been assumed for thepurposes ofthis description that the strip-S is passing from the station 4 to thestation 5. Let it be assumed that it is desired to reduce the stripbeing delivered from the station 4 twenty percent. It is but necessary.to fix the rate of delivery at the station 4 an amount equal tofourfifths of the rate of take-up at the station 5 to result in theprecise dimension desired in the finished size of the strip as at S. For50% reduction the delivery rate at 4 would only be half of thetake-up-rate at 5. Similarly, as is frequently desirable in the temperrolling of strip steel, where 1% reduction is a .deside'ratum, itwouldbe necessary only to correlate the drives between the stations 4and 5, so that the former delivers strip at a rate that is 99% of therate of the take-up 5. 1

If a difierent rolling condition is desired, some adjustment may beeffected by moving the rolls 7 I and 3 apart to some positions I, and.3, as shown in broken lines in Figure 1. The central work roll 2 would,under these conditions, be caused to settle downwardly in a verticaldirection to assume some lower position, as is indicated by the brokenlines 2' in this figure. It is believed that the most efilcient reducingcondition occurs when those radii of the central roll 2, which, ifproduced, would pass through the centers of the rolls l and 3,respectively, are disposed apart. Less angularity than this would, inall probability, effect some lightening of the compressive action for agiven amount of tension, .whereas the increase of this angularitysubstantially in excess. of 120 would cause a corresponding increase incompressive action up to the point where a binding action might arise,with an attendant tearing of the stock.

The apparatus diagrammatically illustrated by Figures 2 and 3 comprisesstationary rolls l and 3, subject to the same adjustmentas describedabove in connection with Figure l, and the central floating roll 2,which. in this case, is of small diameter to lessen the arc of contactbetween the work and adjacent rolls along the lines of highestcompression. Figure 3 is a similar arrangement except in this case thework rolls l..

better adapted in effecting light drafts, such as are encountered in thetemper rolling of strip steel, than for effecting heavier reductions.This is because strip is elongated between the rolls 1 and 2, andelongated again between the rolls 2 and 3, which, since the strip-ismaintained at all times under tension, causes the strip to travel atdifferent speeds past the rolls. The rolls, being idle, must likewisetravel at diflerent speeds, resulting in surface'slippage between therolls l and 2, and between the rolls 2 and 3. The central roll 2 must,in any case, accommodate itself to the relatively slow surface speed ofroll I, which latter is perhaps accelerated to some extent thereby, andto the faster speed of the advance roll 3, which is, in turn, tending tobe slowed down by the roll 2. The resolution of with respect thereto,The roll I3 is carried ation and damage the surface of the strip,particularly, in view of the large arc of contact between the strip andthe central roll 2. The constructions of the following figures in thedrawings are provided to alleviate or obviate altogether this condition.

In Figure 4 there is shown a device comprised of rolls l and 2 arrangedto revolve about Sta-:

tionary axes, which are capable of being horizontally adjusted, as hasbeen previously explained in connection with Figure 1. In this case thecentral roll 2 is journaled for rotation in a vertically movablefloating frame 8, which carries in addition to the roll 2, auxiliaryrolls 9 and In. As the strip moves under tension, the tensile force isresolved in a downward component of the roll 2, as is transmittedthrough the rolls 9 and I0 and the frame 8 in a manner similar to theactionof the floating roll discussed in Figures 1, 2 and 3. Theadvantage derived from this arrangement is attributable to the fact thatthis material is held substantially out of contact with the floatingroll 2, whereby the large arc of frictional engagement over the back ofthe roll is avoided. This brings about a better operating condition,whereby the speed differentials of the several rolls can be betteraccommodated, but does not obviate altogether the slippage attendantupon the elongation of the material between the several rolls,

This latter condition is completely overcome in the arrangement shown inFigure 5, in which the stationarily journaled rolls I and 3, aspreviously described, are matched with floating work rolls 22' carriedin a frame 8', which may be constructed with guide rolls 9, l0, arrangedin the manner of the device illustrated in Figure 4 I and for likereasons, or may be provided with one passed directly between the work,rolls 2--2', as

indicated at S to the same effect. In these arrangements, the surfacesof the rolls 2-2, 9-9, or H, are maintained in spaced relation so thatthey are each free to follow the surface speed of the strip at the pointwhere it comes into engagement therewith, without regard to the speed ofthe other rolls. Herein, as in the constructions previously described,the tension in the strip is resolved into a downward component of theframe 8' which, in turn, is transmitted through the journals of therolls 2-2' to compress the strip confined betweenthe latter and therolls l and 3, respectively. As in the foregoing case cited, thepressures here are directly proportional to the tension-in the strip; sothat a thousand pounds tension would give a downward component oftheframe 8' an amount equal to two thousand pounds to beborne at the twopoints of bearing between the rolls l and 2, 2' and 3, giving acompressive force at each of one thousand pounds.

In, Figure 6 is illustrated another manner in which to give effect tothe principle embodied in Figures 1 to 3, inclusive, but in this case byextremities.

upon arms l5 which are pivoted for rotation upon a center A that iseccentric relative to the stationary axis of revolution A of the centralroll l2, so that, when the roll I3 is lifted along the are C, it willultimately come into tangential engagement with the surface of the workroll l2. The work roll I4 is correspondingly journaled for movement uponarms l6, which, in turn, are pivotally mounted upon a. center A,eccentrically disposed relative to the axis of rev'olution A of the rolll2,-so that, when the roll I4 is raised, as is indicated by the are C,it will be brought into tangential engagement with the surface of thecenter roll l2.

In this arrangement the strip S is caused to pass about the severalrolls in th manner previously described in Figure 1. As the strip istensioned, the rolls l3 and Il are urged upwardly into engagement withthe roll l2, so as to compress the strip therebetween.

The embodiment of Figure 7 works similarly to the Figure 6 constructionin that the central roll 22 is journaled to revolve about a relativelystationary axis A, with the cooperating work rolls 23 and 24 beingjournaled for rotation upon oscillatable arms 25 and 26. The difference.

rolls 23 and 24 are urged toward each other along arcuate paths C and C,respectively, to confine and compress the strip against the centralroll.

In Figure 8, there is shown stationarily journaled rolls 32 and 32'against which movable rolls 33 and 34, respectively, are adapted tobear. The rolls 33 and 34 are carried at the extremities of arms 35 and36, respectively, which are provided with guide rolls 31 and 38 at theirouter Th arms 35 and 36 are pivoted for rotation upon stationary pivotbearings A and A, respectively. The strip enters the arrangement as isshown at S and leaves the arrangement. as is shown at S. Tension on thestrip exerts a lifting force upon the roll 31, which is transmitted bythe arm 35 to the roll 34 to compress the strip against the stationarywork roll 32'. This compressive action is assisted by the downwardmoment resulting from the tensioned strip passing over roll 34.Similarly, in Figure -8, the roll 33 is lifted to bear against the roll32 by the lifting moment the tensioned strip imparts to the roll 33, andthe downward force exerted upon the roll 38. The leverage affordedby thearms 35 and 36 can be arranged to give a compressive force in relationto the tensile force at a ratio of greater than one to one.

In Figures 9, 10 and 11, theinvention is illustrated as applied to amill designed with but one movable work roll cooperating with onestationmaking the central roll l2 stationary with the complementary workrolls I3 and I4 movable stationary work roll 42. In this case, however,

an extension of 44' of the arm is provided upon the far side of thepivotal axis A from the work roll 43, the extremity of which extensionlsprovided with a guide roll 41. The stationary rolls 45 and 46 are placedin the most desirable locations respecting the entry and exit of thestrip ment. Tension on-tl'ie strip S urges the work roll 43 downwardlyin the direction indicated by the are C, and urges the guide roll 41upwardly, as

indicated by the arc C',' and effects a compressive,

action upon the strip passing between the rolls 42 and 43. Thecompressive force may be made greater than a one to one ratio in pportion to work-piece that is somewhat less, due to the compressiveforce afforded by the rolls, than would be required to stretch thework-piece without the presence of such compressive force. Thepossibilities of over-stretching the strip are entirely obviated byvirtue of the fact that the compressive force is a function of thetension in the workpiece, and must always bear. a direct proportionalitythereto. In the preferred embodiment of the inventionjthe work rolls areidle, and the only motive force applied to the work-piece and mill'isthat provided by the take-up mechanism.

. .15 to the mill, the same as in the Figure 9 embodiv,

the tensile force by increasing the length of the arm extension 44'. Inthese single roll embodiments, the block-and-fall' action of thestripupon the movable work roll, which is provident of a force equal to twicethat of the tensile'force in the strip, is realized in substantially itsfull value, and multiplied by the effects of similar action on the guideroll 41, as augmented by the lever 44'. In the embodiments shown inFigures 1 to 7, inclusive, the block-and-fall" action is distributedbetween the two points ofbearing the central roll makes with the otherwork rolls, whereby the downward moment of the central roll (equal totwice the tensile force) is reduced to a value substantially equal tothe tension at each bearing.

Figure 11 is a modified form of the device shown in Figure 10comprising, as in the'latter, stationarily journaled strip guide rollsand 46, a stationarily journaled work roll 42, and a. movable work roll43 cooperating therewith. The latter is carried on an arm 44 with aleverage extension 44'. In this case, however, the extremity of theextension 44! is provided witha bell crank 48 which is adapted forpivotal movement relative to the extension 44' upon a pivot A A isprovided with a roll 41, and upon the opposite side of the pivot isprovided with an armate segment 50 having a plurality of holes 5|adapted to cooperatewith a-hole (not shown) in the extension 44, .intowhich a pin 52 is removably disposed. By withdrawing-the pin, the bellcrank may be turned and fixed at any of the several positions allowed bythe holes 5| to increase the leverage, as when the roll 41' would beextended to position 41, shown in bro- The bell crank upon one side ofthe pivot:

If the take-up is set to a unit pulling force, and is opposed by a forceless than unity applied to the work-piece at the entrance side of themill,

the work-piece will be reduced an amount exactly equal to the-differencebetween the pulling and opposingforces. The tensile and compressiveforces-,automatically attain a balance to give only the desiredreduction, and over-stressing is entirely obviated. 1

In conventional types of mills, the work rolls are automatically driven,and are set to some predetermined spacing intended to be provident ofthe size to which it is desired to reduce the work-piece.

In such case, the work rolls divide the strip into two parts withrespect to tension applied thereto, since the work rolls provide abearing behind which tension may be applied largely independently of theamount of tension applied forwardly of this bearing. The opposingforces, in the case of mills having driven work rolls (whether drivendirectly or driven by contact with driven backing-up rolls), provide aforwarding moment to the strip which is in addition to and combined withthe pull of the take-up to advance the work-piece through the mill, eventhough there may be a force opposing such advancement upon the entranceside 4 way has presented itself to correlate these facken lines, or todecrease the leverage as when the roll of 41 is made to'assume theposition indicated by the broken lines 41 This arrange tors, or formaking them interdependent.

. To obtain the exact amount of reduction desired, be it ever so smallor large, and to overcome all. of the disadvantages of the prior art, itis but necessary, in practicing the-presentinvention, to proportion the-pulling force and the opposing force on the work-piece in such ratiothat the latter force has the same relation to the former, as thedesired finished dimensions of the material bear to the unreduceddimension thereof, and a work-piece of the desired finished dimensionsfollows as an inherent'function of the device. This may be easilyeffected by connecting the delivery and take-up stations throughdifferential gearing, by hydraulic drives, or'by suitable electricalinstrumentalities, so that the rates of delivery may be-pre-set beforethe commencement of the operation to provide the des' red reduction. Themill is then threaded up and the power applied. All ofthe various forcesare brought into balance to reduce the work-piece the required amountwith extreme accuracy. If, during the' reducing operation a greater orlesser amount of reduction becomes desirable, this may be effected byadjusting the one simple control to diminish or increase the ratio ofthe opposing force to the pulling force, respectively.

There are many ancillary advantages accruing to the use of the presentinvention, such as absolute uniformity of contact between work rolls andwork-piece. and the automatic alignment of the rolls in operation. Inmany of .the embodiments, the work-piece under tension so encircles therolls as to resist any tendency of tion operations that subjectwork-pieces to tensile and compressive stresses in a straight line.

Although the greatest benefits of the inven-' tion may be enjoyed by theuse of idle work rolls, it is not intended to' preclude the use-ofdriven rolls, since many suitable arrangements are possible by the useof driven rolls should this prove to be desirable. It is recognized thatto adapt the present invention to tandem operations, powered work rollswould be necessary to assist the passage of the work-piece through sucha mill, and tandem operations are within the purview of the presentinvention. Similarly, although rolls have been used herein, for purposesof illustration, as preferred forms of working instrumentalities, itwill be appreciated that other forms of compressive dies may be em-,ployed. Further, it is contemplated that proper lubrication shall beprovided in all of those operations wherein there occurs a substantialamount of slippage between the work rolls and the work-piece, as is thecase in the embodiments illustrated in Figures 1 to 3, etc.

In cases where it is desired to have a compressive force disproportionalto the tension, it will be understood that additional pressure may beapplied as by screw-downs to the floating roll 2 or roll frame 8-8,shown in Figures 1 to 5. inclusive, in augmentation of the downwardcomponent of these members as provided by the tension in the strip.Increasing compressive force is obtainable by permitting the work rolls1 I and 3, in these same figures, to be displaced away from each otheragainst the resistance of heavy springs so that the greater thedisplacement the. greater would be the compression to which such springswould be subjected, giving an increasing compressive forcedisproportional to supply and take-up reels, and the reducing rolls.respectively. to facilitate the constant and uniform tensioning andfeeding of the work. This would eliminate from consideration theeverchanging relationship existent between the winding and pay-oft reelarbors, occasioned by the stocks unwinding from the latter (thuslessening its effective diameter) and building upon the former (thusincreasing its effective diameter).

This purpose may be likewise served by intergearing the pay-off andpull-out reels by automatically compensating fluid, mechanical, or

electrical differential mechanism, to the endthat,

once the device is set, and the reducing operation commenced, the workwill be subjected to uni- .form, constant tension and reducingconditions throughout the entire operation, or until an alteration inthe amount of reduction is desired.

Devices for giving effect to this result are so well known in this andrelated arts as to render more specific illustration thereofsuperfluous.

It will be understood, therefore, that many modifications of theinvention may be made without departing from the scope thereof, and itis not intended that I be limited to the specific embodiment shown,other than as is rendered necessary by the recitations of the appendedclaims.

I claim:

' tensile stress upon such a body; simultaneously I tions thereofintermediately of its tensioned exthe increase in tension causing thisaction. v

Similarly, springs, weights, or screw-downs, could be applied to liftthe axes of the rolls l3 and IS in Figure 6, or to draw the axes of therolls 23 and 2ltogether so as to provide an augmented compressive force.Similar adaptations could be effected upon the instrumentalities shownin the other views.

In those embodiments providing the floating central roll,'it will beunderstood that suitable vertical guidingmeans are contemplated toprevent such rollers from lateral displacement, as

also are suitable jacks or mill crane appurtenances, for the raising andlowering of such rollsmuch iristhe' manner of contemporary rolling milloperation Although not illustrated in the drawings, it will beappreciated that constant-speed pull-out and pay-off means may beemployed between the and incident to the imposition of said tensilestress, subjecting a tensioned portion of said body to a compressivestress that is derived from said tensile stress, and effecting relativemovement between said body and the points of application of saidcompressive stress to subject successive tensioned portions of said bodythereto.

2. The method of reducing long bodies capable of plastic deformationwhich includes tensioning such a body while compressing successiveportent, and controlling. the amount of compression by varying theamount of the tension.

3. The method of reducing long bodies capable of plastic deformationwhichincludes-applying tensile and compressive forces to such a bodysimultaneously and interrelatedly until its yield point has beenexceeded, said method being char-- acterized by the fact that thecompressive force is derived from the tensile force prevailing in theunreduced portions of the body, and varies directly therewith.

4. The method of reducing long bodies capable of plastic deformationwhichincludes forwarding such a body by a unit pulling force thereupon,resisting said forwarding movement by a force less than unity to tensionthe material in motion, and compressing successive portions of saidmoving body intermediately of its tensioned extent by a compressiveforce which is derived from said resisting force and which varies assaid resisting force varies.

, and compressing successive tensioned portions of said moving body by acompressive force applied posteriorly of the point of application of theresisting force which varies as said tension varies;

6. The method of reducing long bodies capable of plastic deformationwhich includesmov ing such a body from a delivery point to a take-uppoint, fixing the delivery rate of said material at unity, pulling saidbody toward the take-up point by a force provident of a rate exceedingunity to tension said body, exerting compressive forces upon tensionedportions of said body intermediately of the delivery and take-up points,which forces are derived from the tension and vary in response tovariations in the tension, and increasing the pull on the body until itsyield point has been exceeded and the desired reduction performed.

'7. The method of reducing long bodies capable of plastic deformationwhich includes tensioning and compressing a body simultaneously, saidtension, being applied anteriorly of the points of application of thecompression, saidcom pression being derived from said tension andvarying in response to variations in the tension.

-8. The method of reducing long bodies capable of plastic deformationwhich includes simultaneously imposing tensile and compressive stressesupon such a body, the compressive stress being derived from the tensilestress existing in the body anteriorly of the compression zone so as tovary as the tensile stress varies, increasing said stresses until thecombined stresses exceed the yield point of the material which isreduced in thickness thereby, and continuously effecting such reductionupon successive portions of said body lengthwise thereof. 1

9. Reducing metal strips, wire, and the like, by subjecting successiveportions of a length of such material to the action of compressive dies,actuating said dies to'compress the material by tensioning it upon itsapproach side of the dies continuousl to reduce the material passingtherethrough.

10. In the rolling of metals, the improvement which comprises tensioningthe work-piece anteriorly of the rolls, and controlling the rollingpressure by said tension so that thepressure varies as the tension andas a function of the latter.

11. In the rolling of metals, the improvement which comprises passing awork-piece between work rolls, and effecting compression of thework-piece bysaid rolls by placing the workpiece under tensionanteriorly of said rolls; the compression being derived from saidtension and varying directly therewith.

12. In the rolling of metals, the improvement which comprises advancinga length of stock through work-rolls by a unit pulling force, resistingthe advancement of the stock through said work rolls by a force lessthan unity to tension the stock anteriorly of the rolls; and cansingsaid work rolls to compress the stock, as a result of the institution ofthe tension therein, with a force bearing a one to one ratio or greaterto the tensile force.

13. In the reduction, of metals, the improvement which comprises inmoving a lengthof stock between a movable compressive die. element and arelatively stationary compressive die element so that when the stock istensioned anteriorly of the dies the movable die element is urged towardthe stationary element to subject the stock to compressive stress.

14. In the reduction of metals, the improvement which comprises inmoving a length of stock between a movable compressive die element and arelatively stationary compressive die element so that when the stock istensioned anteriorly of the dies the movable die element is urged towardthe stationary element to subject the stock to compressive stress,pulling the stock' through said die elements by a unit pulling force,and opposing themovement of the stock to said die elements by a forceless than unity.

15. In the reduction of metals, the improvement which comprises inmoving a length of stock between a movable compressive die element andarelatively stationary compressive die element so that when the stock istensioned anteriorly of the dies the movable die element is urged towardthe stationary element to subject the stock to compressive stress,pulling the stock.

through said die elements by a unit pulling force, and opposing themovement of the stock to said die elements by a force less than unity,said opposing force being in the same proportion to the pulling force,substantially, as the reduced dimension of the material is to theunreduced dimension thereof.

16. In the reduction of metals, the improvement which includes moving alength of stock between relatively movable compressive die elements sothat when the stock is tensioned anteriorly of the dies the die elementsare urged together to compress the stock therebetween, tensioning thestock, and effecting relative movement between the stock and dieelements to subject successive portions of its length to the compressiveaction thereof.

17. In the reduction of metals, the improvement'which'includes disposinga length of stock between relatively movable compressive die elements sothat when the stock is tensioned anteriorly of the dies the die elementsare urged together to compress the stock therebetween, tensioning thestock, and effecting relative movement between the stock and dieelements to subject successive portions of its length to the compressiveaction thereof, the compressive force a length of material between saidstations; relatively movable compressive dies constructed and arrangedto bear upon said material within the tensioned portions thereofactuable in response to the tension to exerta compressive forceproportioned to the tension in the material and varying as the latter.

19. Apparatus of the class described, means for tensioning a length ofmaterial between two stations along its length; means responsive to thetension in said'material and varying as the latter varies forcompressing the latter at tensioned portions thereof, and means formoving said material past said last-named means while under tension.

20. Apparatus of the class described comprising means for simultaneouslyand interdependently tensioning and compressing a metal body, thetensioning means being effective to tension the body anteriorly of thecompressing means, and the latter means being actuable in directresponse to the anterior tension to compress the material proportionallyto the tension.

21. A rolling mill comprising a plurality of relatively movable rolls;means for moving a length of stock in cooperative relation to said rollsunder tension; said rolls being constructed and arranged to bear uponsaid stock with a force at least equal to the tensile force to which thestock is subjected upon the approach side thereof, and in responsethereto.

22. A rolling mill comprising a plurality of relatively movable rollsbetween some of which stock to be reduced is adapted to pass, and aboutsome of which said stock is passed before and after, respectively,reduction; said mill being characterized by the fact that thecompressive force exerted by the rolls upon the stock is a function oftension in the stock which varies as the tension varies.

23. A rolling mill for reducing long lengths of metal stock comprising aplurality of rolls; a mounting for said rolls including means responssive to tension in the stock anteriorly of said rolls for urging therolls together to compress the stock.

24. A rolling mill for reducing long lengthsof metal stock comprising aplurality of rolls journaled on relatively movable axes of revolution;means for moving and tensioning stock in reducing engagement withcertain of said rolls, including means responsive to tension in thestock for urging said rolls together to compress the stock; said meansallowing the compression of the stock between separate groups of rolls,while effectively maintaining the compressive groups of said rolls, andcontiguous portions of the stock under compression, in spaced relation.

25. A rolling mill for reducing long lengths of metal stock comprising aplurality of work rolls; two of said rolls being relatively stationarilyjournaled; two other of said rolls being adapted for cooperationrespectively, with said stationary rolls, and being joumaled in ahousing movable relative to said stationarily journaled rolls, whereby,when a work-piece is positioned to extend between adjacent portions ofthe cooperating relatively stationary and movable rolls, respectively,and is tensioned, the movable rolls are urged toward the stationaryrolls to compress contiguous portions of the work-piece.

26. A rolling mill for reducing long lengths of metal stock comprising arelatively stationary roll, and a movable roll; a mounting for themovable roll allowing the latter to approach and recede from saidstationary roll; and means on said mounting for engaging a work piece inthe mill, whereby, when the work-piece is tensioned said means urges themovable roll against the stationary roll to compress contiguous portionsof the work-piece.

27. The method of reducing long metal bodies which includes:continuously advancing lengths of such a body to compression means;tensioning the body upon the approach side of the compression means tostress it; compressing said body by said means with a force derived fromand proportional to the tensile stress prevalent in the approachingbody; increasing the tensile stress to efiect simultaneous increase inthe compressive force until the coacting stress and force combinedexceed the elastic limit of the body an amount sufficient to impart theelongation and reduction in area thereto desired.

PATRICK H. HUME.

